Hydrophilic lubricity coating for medical devices comprising a hydrophobic top coat

ABSTRACT

The present invention relates to a medical device for insertion into the body wherein the device has at least one surface which periodically comes into contact with a second surface. The first surface comprises an improved lubricious coating having a first hydrogel layer and a second hydrophobic top coating which prevents the hydrogel coating from prematurely absorbing too much moisture. The hydrophobic top coating comprises at least one hydrophilic surfactant which acts as a carrier to facilitate removal of the hydrophobic top coating upon entry into an aqueous environment.

FIELD OF THE INVENTION

[0001] This invention relates to a coating lubricity for insertable orimplantable medical devices having improved lubricity, which comprises afirst coating of a water swellable polymeric substance and a secondcoating having a hydrophobic component and a hydrophilic surfactant.These coatings find particular utility for the balloon portion of acatheter device.

BACKGROUND OF THE INVENTION

[0002] Water soluble, biocompatible compounds that impart lubricity tothe surface of otherwise non-lubricious materials are desirable for useon medical devices which are inserted or implanted into the body. Suchmedical devices may include catheters that are utilized to deliver astent, stent-graft, graft or vena cava filter, balloon catheters, otherexpandable medical devices and so forth. The industry has turned tohydrophilic lubricious coatings in order to overcome problems withcommonly used hydrophobic coatings such as silicone, glycerine or oliveoil.

[0003] Hydrophobic coatings have been known to bead up and run off whenexposed to an aqueous environment, lose initial lubricity rapidly, andlack abrasion resistance. Residual amounts of silicone have also beenknown to cause tissue reaction and irritation in patients. The loss oflubricity can lead to discomfort during insertion into a patient, anddamage to blood vessels and tissues due to frictional forces duringinsertion or removal of the device.

[0004] One class of polymeric substances which dissolve or swell in anaqueous environment, often referred to as “hydrogels,” are capable ofmanifesting lubricity while in a wet state, and are popularly utilizedas lubricious coatings for medical devices. When hydrated, thesesubstances have low frictional forces in humoral fluids includingsaliva, digestive fluids and blood, as well as in saline solution andwater. Such substances include polyethylene oxides, optionally linked tothe substrate surface by urethane or ureido linkages or interpolymerizedwith poly(meth)acrylate polymers or copolymers; copolymers of maleicanhydride; (meth)acryl amide polymers and copolymers; (meth)acrylic acidcopolymers; poly(vinyl pyrrolidone) and blends or interpolymers withpolyurethanes; and polysaccharides.

[0005] These water soluble coating materials, while popular because theyprovide excellent lubricity and biocompatibility, may be sensitive tomoisture.

[0006] A problem associated with the moisture sensitivity of suchhydrogels is that they may prematurely uptake ambient moisture andbecome sticky or tacky. This can result in undesirable adhesion of themedical device to itself, to other devices if mass packaged, or to anyother surface to which it comes in contact during sterilization orstorage. In the case of dilatation balloons, after sterilization orstorage these hydrogel coatings can become delamninated from thepolymeric surface upon expansion of the balloon because the foldedsections stick to one another by cross-polymerization or bridging.

[0007] In the case of metal wires, such as guide wires, which may bepackaged in rolls, the “self adhesive” effect can lead to removal ofsome of the coating, leaving pinholes or complete failure of the coatingfrom the surface of the wire as it is uncoiled.

[0008] These problems are discussed in U.S. Pat. No. 5,509,899 issuedApr. 23, 1996 to Fan et al. Fan et al. teaches a medical balloon andcatheter which is wrapped and folded upon itself and in which theballoon is free of bridging and adhesion between abutting surfaces. Theballoon has a base of a continuous polymeric surface which isexpandable. On the polymeric surface is disposed a lubricious,biocompatible hydrogel coating and a thin, lubricious, blood-compatiblecoating is disposed on the hydrogel coating and adheres to it to preventabutting surfaces of the folded polymeric surfaces from adhering to eachother during inflation and to prevent delamination of the hydrogelcoating and/or rupture of the balloon. Preferably, the blood-compatiblecoating is polyethylene glycol, methoxy polyethylene glycol or mixturesthereof having a molecular weight of between about 100 and 20,000 gramsper gram mole. The blood-compatible coating is applied as ananti-blocking agent. See column 2 lines 18 to 37.

[0009] The present inventors have found a coating for medical deviceswhich avoids the aforementioned problems comprising a first coating of ahydrogel polymeric substance, and a second coating of a hydrophobicsilicon having a hydrophilic surfactant which can impede blocking orsticking of two surfaces for improved lubricity, as well as the shelflife.

SUMMARY OF THE INVENTION

[0010] The present invention relates to a medical device for insertioninto the body wherein the device has at least one surface whichperiodically comes into contact with a second surface. The first surfacecomprises an improved lubricious coating having a first hydrogel layerand a second hydrophobic top coating which prevents the hydrogel coatingfrom prematurely absorbing too much moisture. The hydrophobic topcoating comprises at least one hydrophilic surfactant which acts as acarrier to facilitate removal of the hydrophobic top coating upon entryinto an aqueous environment.

[0011] The medical device may be insertable or implantable, and/or itmay be an expandable medical device such as a balloon catheter, or itmay be an elongated device designed for manipulation within the body.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012]FIG. 1 is a side view of a catheter with a balloon tightly wrappedand folded for insertion for a medical procedure.

[0013]FIG. 2 is a perspective view of a dilatation catheter thatincludes the inflated coated balloon of FIG. 1.

[0014]FIG. 3 is a schematic representation of an elongated medicaldevice of the invention.

[0015]FIG. 4 is an enlarged cross-sectional view of the coatings asviewed on either the balloon of FIG. 2 or on an elongated medical deviceas in FIG. 3.

DETAILED DESCRIPTIONS OF THE PREFERRED EMBODIMENTS

[0016]FIG. 2 is a schematic representation of an inflated dilatationballoon catheter of the present invention, illustrated generally at 10.The inflated balloon 14 is mounted at the distal end of an elongatedflexible shaft 12. Except as noted herein, catheter 10 is conventionalin its construction, providing a lumen communicating with the interiorof the balloon 14, for inflation and deflation of the balloon, and otheroptional features conventional in the dilatation catheter art. Theballoon 10, has an inflated configuration, illustrated in FIG. 2 and ismade up of three main portions: the body 24, the cones 26 and the waistportions 28. FIG. 1 illustrates the lubricious hydrogel coating 13 andthe hydrophobic top coating 15 on the body 24, the cones 26 and thewaist 28. FIG. 2 illustrates a coating which is of a uniform thicknesson all parts of the balloon. A coating gradient could also beestablished whereby the coating weight on the body 24, is less than thecoat weight on the cones and the coating is thickest on the cone portionclosest to the waist and on the waist itself.

[0017] Balloons are typically made by a process by extruding the balloonmaterial into a tubular preform, blow molding the balloon, andannealing. The tubular preform may be stretched prior to blowing. Thecoatings of the present invention may be applied to the tubular preformprior to blowing. In this case, the coating will form a gradient wherebythe coat weight will be inversely proportional to the amount ofexpansion the different parts of the balloon goes through. For instance,the lowest coat weights will be found on the body of the balloon whichexpands the most. The coat weight will be the heaviest on the waistportion which may expand only slightly, stay the same, or even decreaseslightly in size.

[0018]FIG. 3 is a schematic representation of an elongated medicaldevice which may be a guide wire, catheter, cannula, fiber optic deviceand the like. Device 40 extends between proximal end 16 and distal end18 and includes an elongate body 41. A control mechanism 17 mayoptionally be provided at or near the proximal end of device 40 tofacilitate manipulation of the device and/or activation of functionalstructure provided on the device, such as drug delivery or ballooninflation lumen. Device 40 may also optionally be provided with afunctional structure 19, such as an inflatable balloon, deployablestent, drug delivery mechanism, or the like, typically at or near thedistal end 18.

[0019] Very little limitation is placed on the material for the elongatebody 41. Most devices will have a relatively flexible body, such as whenthe device 40 is a catheter or guide wire. However, the invention mayalso be used with inflexible transcutaneous devices such as a needle.Body 41 may be made of organic high polymer materials such as polyamide,polyester, polyvinyl chloride, polystyrene, polyacrylate,polymethacrylate, polyacrylonitrile, polyacrylamide, polyethylene,polypropylene, polyurethane, polyvinyl acetate, silicone resins andcopolymers and blends thereof. However, various inorganic materials suchas glass, ceramic, stainless steel, and super elastic metal or shapememory alloy such as Ni—Ti, and the like may be employed on part or allof body 41. Body 41 may also be formed as a composite of differentmaterials which are laminated together. Depending on the nature of thespecific device 40, body 41 may be provided with one or more lumens,electrical connectors, optical fibers or the like, as is well known inthe medical art.

[0020] One specific embodiment of device 40 is a balloon catheter forangioplasty and the like, in which case functional structure 19 willinclude an inflatable balloon, located very near the distal end 18 ofdevice 40. The elongate body 41 will be a flexible tube, typicallypolymeric, containing at least an inflation fluid lumen for the balloonand a control mechanism 17 located at the proximal end 16 of device 40of conventional design will be provided for manipulating the catheter tothe desired site in the body and for causing the balloon to inflate anddeflate as desired. Such a catheter may also be provided with a softdistal tip as part of functional structure 19 to facilitate maneuveringthe balloon to cross a lesion and/or a guide wire lumen to allow thecatheter to be inserted over a guide wire.

[0021] Another specific embodiment of device 40 is a guide wire in whichcase body 41 may be a metal wire. There may not be any control mechanism17 present at the proximal end 16 and the distal functional structure 19at the distal end 18 may simply be a conventional coiled or softpolymeric tip.

[0022] The coated portions may be body 41 of device 40 which is coatedin FIG. 3 with a hydrogel coating 43 and the hydrophobic top coating 45of the present invention.

[0023] If the functional structure 19 is a dilatation balloon, theballoon may also be coated as shown generally at 10 in FIG. 2 whereinthe inflated balloon is coated with hyrogel coating 13 and hydrophobictop coating 15.

[0024]FIG. 4 is a schematic cross-sectional representation of a balloonwall 20 having a lubricious hydrogel coating 23 disposed thereon and ahydrophobic top coat 25 disposed on the hydrogel coating 23. The wallmay be formed from any flexible polymeric substance. In some preferredembodiments the balloon wall if formed from polyether block amides, suchas Pebax® 7033 or 7233; polyester block ethers such as Arinitel® EM 40;polyethylene terephthalate; and nylon. FIG. 4 may also be representativeof a coated tubular preform or an inner lumen for carrying fluids.

[0025]FIG. 5 is a schematic cross-sectional representation of a guidewire 30 having a lubricious hydrogel coating 33 disposed thereon and ahydrophobic top coat 35 disposed on the hydrogel coating 33. The guidewire may be formed from a metal and may preferably be a shape memoryalloy such as Ni—Ti alloy.

[0026]FIG. 4 and FIG. 5 are expanded views of such medical devices andare not meant to limit the ratio of the coat weight of the hydrogelcoating to the top coat. The coat weights may vary.

[0027] The hydrogel coating has a thickness between about 1 and 10 μm.The hydrogel coating is a lubricious, hydrophilic material which has theability to dissolve or swell upon exposure to an aqueous type ofenvironment. Water soluble polymers can be used which are generallychain-structured, non-crosslinked polymers having a hydrophilic groupsuch as —OH, —CONH₂, —COOH, —NH₂, —COO—, SO₃, AND NR₃ ⁺, where R isalkyl or hydrogen.

[0028] Natural water soluble polymers may also be utilized such ascarboxymethyl cellulose, methyl cellulose, hydroxyethyl cellulose andhydroxypropyl cellulose, heparin, dextran, modified dextran andchondroitin sulphate.

[0029] Synthetic water soluble polymers include the polyalkylene glycolsand polyoxyalkylene glycols such as polyethylene oxide, polyethyleneoxide/polypropylene oxide copolymers and methoxypolyethylene oxide;copolymers of maleic anhydride including methyl vinyl ether-maleicanhydride copolymers; pyrrolidones including poly(vinylpyrrolidone);acryl amides including poly(N-alkylacrylamide); poly(acrylic acid);poly(carboxylic acids); poly(vinyl alcohol); poly(ethyleneimine);polyamides; water soluble nylons; polyurethanes; and so forth.

[0030] Derivatives of any of these polymers may be utilized providingthat enough of the basic structure of the polymers above that provideswater sensitivity, solubility or dispersibility is retained allowing thepolymer to uptake enough water to swell or partially dissolve enoughupon exposure to moisture to provide lubricity in such a way to reducefrictional forces between the surface it is coated on and anothersurface such as tissue, metal or polymeric surfaces. Water insolublederivatives may be employed as long as they have the freedom in themolecular chain and can be hydrated. Examples include esterifiedpolymers, salts, amides, anhydrides, halides, ethers, hydrolyzates,acetals, formals, alkylols, quaternary polymers, diazos, hydrazides,sulfonates, nitrates, and ion complexes which are obtained bycondensation, addition, substitution, oxidation, or reduction reactionsof the above-mentioned water soluble polymers. Also used are polymerscrosslinked with substances having more than one reactive functionalgroup such as diazonium, azide, isocyanate, acid chloride, acidanhydride, imino carbonate, amino, carboxyl, epoxy, hydroxyl, andaldehyde groups.

[0031] Copolymers with vinyl groups, acrylic acid, methacrylic acid,diene compounds and maleic anhydride have been preferably utilized.

[0032] Carboxylic acid-containing polymers may be preferably used ascoating materials in the invention.

[0033] In another preferred embodiment, a hydrogel of polyethylene oxidemay be captured in an interpenetrating crosslinked acrylic polymernetwork by polymerizing a mixture of an acrylic monomer compositioncomprising a monomer having plural (meth)acrylate groups andpolyethylene oxide, thereby providing a hydrogel coating. The lubricityof such a coating can be modified, for instance by reaction of theactive hydrogen groups of the polyethylene oxide with an active hydrogenreactive compound such as an isocyanate, an acid chloride, an anhydride,an alkyl halide, etc. Varying the ratio of monomer to polyethyleneglycol over the length of the coating can also be used to create alubricity coating gradient.

[0034] The hydrogel coating is then top coated or treated with ahydrophobic coating such as a silicone based coating. These siliconesmay be of the siloxane type. In a preferred embodiment of the presentinvention, Dow Coming® DC 360 is utilized utilized as the hydrophobicsilicone agent. Other hydrophobic compounds useful to the presentinvention include chlorotrifluoroethylene (CTFE oil), polyphenyl ethersand so forth.

[0035] The hydrophilic surfactants useful to the present inventioninclude polyoxyethylene modified silicones which are nonionicsurfactants useful for addition to the hydophobic top coating. Theseinclude the Silwet® surfactants manufactured by Witco. These are linearpolydimethylsiloxanes grafted with EO and PO through hydrozylation, orthrough the Si—O—C bonds. By varying the ratio of EO and PO and byvarying the molecular weights, a broad range of Silwet® surfactants areavailable on the market which offer unique properties and performanceadvantages over other conventional organic surfactants. A hydrophilicsurfactant is admixed with the hydrophobic silicone by dissolving in acosolvent or a mixture of solvents. The surfactants have both ahydrophobic portion, usually a long chain hydrocarbon, and a hydrophilicportion allowing them to have some compatibility with the silicone agentand some water solubility as well. The hydrophilic surfactant may be analkylene glycol or a polyoxyalkylene glycol of the ethyleneoxide/propylene oxide copolymer type. Specific examples include thePluronic® and Pluronic® R ethylene oxide(EO)/propylene oxide(PO) blockcopolymer surfactants available from BASF. Pluronic® surfactants areblocks of EO/PO/EO having from about 10% to about 80% EO. Pluronic® Rsurfactants are PO/EO/PO blocks. The molecular weights ranges from about1800 to about 8500 g/mole and have from about 10% to about 80% EO. Thereversed hydrophobic and hydrophilic blocks create differences inperformance versus the EP/PO/EO blocks.

[0036] Other useful hydrophilic surfactants include polyethylene oxidebased block copolymers such as the Tetronic® series of surfactants madeby BASF. Tetronic® surfactants are tetrafunctional block copolymersderived from the sequential addition of EO and PO by ethylene diamine.The amine moiety in these surfactants provides slightly cationicproperties and contributes to thermal stability. The molecular weight ofthese compounds ranges from about 2600 to aobut 20,500 g/mole and theycontain from about 10% to about 80% EO.

[0037] In other preferred embodiments of the present invention,polyoxyethylene castor oil derivatives are utilized as the hydrophilicsurfactant. Polyoxyethylene castor oil derivatives are a series ofmaterials obtained by reacting various amounts of ethylene oxide witheither castor oil or hydrogenated castor oil. Several different types ofmaterials are commercially available, one series being the Cremophor®series from BASF including Cremophor® EL 35 and Cremophor® RH 40.

[0038] Nonionic hydrophilic surfactants useful to the present inventioninclude decyl and tridecyl alcohol ethyoxylates. Commercially availableexamples include the Iconol® series made by BASF including Iconol® NPand Iconol® OP. These compounds have from about 4% to about 70% byweight EO concentration. Other similar nonionic surfactants includeIcomeen® fatty amine ethoxylate surfactants; Klearfac® phosphate estersurfactants; Plurafac® linear alcohol alkoxylate surfactants; Pluracol®E polyethylene glycols; Pluracol® W polyalkoxylated polyethers; Sokalan®CP acrylic acid or maleic anhydride copolymers; and so forth.

[0039] The solvent mixture may be a blend that will solubilize both thehydrophobic silicone agent and the hydrophilic surfactant. Thiscosolvent mixture may preferably include isopropanol and aliphatichydrocarbons such as heptane or hexane, for instance. Other useful polarsolvents may include ethanol, methanol, stearyl alcohol, ethyleneglycol, propylene glycol, glycerin, water and so forth. Other usefulnon-polar solvents include mineral spirits; aromatic hydrocarbons suchas toluene and xylene; chlorinated hydrocarbons such asperchloroethylene, methylene chloride, chloroform, carbon tetrachloride,1,1,1-trichloroethane; fluorocarbons and so forth. The hydrophobicagent, i.e. silicone, and the hydrophilic surfactant may then be coatedout of this cosolvent mixture.

[0040] The hydrophilic surfactant is used at concentrations in solventof from about 1% to about 90%, preferably from about 1% to about 30% andmost preferably from about 5% to about 20%. The hydrophobic agent isused at concentrations in solvent from about 1% to about 30%, preferablyfrom about 1% to about 10% and most preferably from about 2% to about5%.

[0041] The hydrophobic compound and the hydrophilic surfactant may bedissolved in a solvent or mixture of solvents. Useful solvents includealcohols, aliphatic hydrocarbons, aromatic hydrocarbons, chlorinatedsolvents, esters, glycols, glycol ethers, ketones, and so forth. Polarsolvents include alcohols, glycols, water and so forth. Specificexamples include ethanol, methanol, isopropyl alcohol (IPA), stearylalcohol, ethylene glycol, propylene glycol, glycerin, water, methylethylketone (MEK) and so forth. Non-polar solvents include aliphatichydrocarbons such as heptane and hexane; aromatic hydrocarbons such astoluene and xylene; chlorinated hydrocarbons such as perchloroethylene,methylene chloride, chloroform, carbon tetrachloride,1,1,1-trichloroethane; fluorocarbons; mineral spirits and so forth.Typically, a cosolvent mixture of a polar solvent, such as isopropanol,and a nonpolar solvent, such as heptane, may be utilized.

[0042] These coatings may be utilized on any insertable or implantablemedical instruments or devices including guide wires, catheters,dilatation balloons, stents, stent grafts, grafts, vena cava filter,inflation lumens and so forth.

[0043] Balloons are typically made of polymeric materials includingnylon, Selar®, polyether-polyester block copolymers (i.e. Hytrel®),Pebax®, polyethylene terephthalate, polytetrafluoroethylene, polyvinylchloride, polyurethanes, polyetherurethanes, polyesterurethanes,polyurethane ureas, polyurethane siloxane block copolymers,polyethylene, polypropylene or other similar extrudable thermoplastic,polymeric materials, or composites thereof. Such materials are typicallyinherently non-lubricious making it necessary to add some type oflubricious coating to the surface in order to advance the device throughthe blood vessel more easily.

[0044] One specific embodiment of a medical device of the presentinvention is a balloon catheter for angioplasty and the like, in whichcase the functional structure will include an inflatable balloon,located very near the distal end of the device. The elongate body willbe a flexible tube, typically polymeric, containing at least aninflation fluid lumen for the balloon. A control mechanism of theconventional design will be provided for manipulating the catheter tothe desired target site in the body and for causing the balloon toinflate and deflate as desired. Such a catheter may also be providedwith a soft distal tip and/or guide wire lumen to allow the catheter tobe inserted over a guide wire.

[0045] Another specific embodiment of a medical device of the presentinvention is a guide wire in which case the body may be a metal wire,such as a Ni—Ti alloy. In this case, there may not be any controlmechanism present at the proximal end and the distal functionalstructure may be a conventional coiled or soft polymeric tip.

[0046] The coating of the present invention may be utilized on any orall of the structures of the medical device. These coatings have foundparticular utility for dilatation balloons and for guide wires. In thecase of the dilatation balloon, the coating will prevent the polymericsurfaces from adhering and sticking together in the folded state. Ahydrogel coating, by itself, may bridge and ultimately cause rupturingof the balloon upon inflation. The hydrophobic top coat having thehydrophilic surfactant, will improve the shelf life of the foldedballoon by preventing the hydrogel coating from up taking too muchmoisture and bridging.

[0047] In the case of guide wire lumens, large lengths of the wire areoften rolled up together with adjoining surfaces in contact with oneanother. The coatings of the present invention prevent the hydrogelcoating from bridging and sticking to itself which can ultimately causecoating to be pulled away from the wire surface thereby leaving barewire which in turn can lead to discomfort during insertion into apatient and ultimately tissue damage.

[0048] The device is first coated with the hydrogel coating. Thiscoating provides the lubricity. Hydrogel coatings typically improvelubricity by uptaking water which allows them to become slippery andlubricious.

[0049] After coating, the device is preferably dried using heat andsubsequently exposed to UV light, for instance, to crosslink or cure thehydrogel coating.

[0050] The device is then coated with the secondary coating or topcoating which comprises the hydrophobic silicone compound and thehydrophilic surfactant. This is coated out of solution. This top coatingprotects the hydrogel coating from absorbing too much ambient moistureand becoming sticky. In the case of a dilatation balloon which is foldedupon itself prior to use, the bridging or adhesion of the coating can beso severe that the balloon ruptures upon inflation. Upon insertion ofthe device into a bodily orifice, and exposing it to bodily fluids, thehydrophilic portion of the surfactant allows the top coating to bewashed away. The biocompatibility of the surfactant allows it to beeasily eliminated from the body without excessive tissue irritation. Thesurfactant, with its hydrophobic portion, conveys the silicone agentwith it, thereby removing the top coating and allowing the lubriciouscoating to swell upon exposure to the aqueous environment.

[0051] The medical device, i.e. balloon, may be coated by dipping,spraying, wiping, and so forth.

[0052] The following non-limiting examples further illustrateembodiments of the present invention.

EXAMPLES Hydrogel Coating 1

[0053] A catheter useful for angioplasty having a balloon with a 3.0 mmdiameter and a length of 20 mm was used in this example. The balloon wascoated with a high molecular weight polyethylene oxide coating which hada 2,2′-azobis isobutyro-nitrile catalyst (both from Aldrich Chemical).The coating was subsequently dried and cured under UV radiation tofacilitate crosslinking of the polyethylene oxide.

Example 1

[0054] A solution of 4% Dow Coming® DC-360 polydimethyl siloxane and 10%Pluronic® 31 R1, PO/EO/PO block copolymer, from BASF in 1:1 (volume)isopropanol and heptane cosolvent mixture was prepared.

[0055] The balloon coated with Hydrogel Coating 1, was inflated underlow pressure (about 2 atmospheres), dipped into the solution (above) for10 seconds, removed, and dried in a 50° C. oven for 2 hours. The balloonis then deflated and placed into a 2.0 mm diameter balloon protector andethylene oxide sterilized in a 13 hour cycle.

Comparative A

[0056] A balloon is coated only with the hydrogel coating 1.

Comparative B

[0057] A balloon is coated with the hydrogel coating 1 and a top coatingof Dow Coming® DC-360 without any hydrophilic surfactant. TABLE IExample 1 Comparative A Comparative B Balloon Opening 25 60 29 Pressure(psi) Lubricity (grams) 6 5.5 11

[0058] As can be seen from the data, the balloon coated with the methodof the present invention, Example 1, exhibited the best overallperformance of low opening pressure and low frictional forces.

Example 2

[0059] The balloon coated with the hydrogel coating, above, was treatedwith the second coating which was a solution of 4% polymethylsiloxane(DC-360) and 10% Cremophor® EL 35 as the hydrophilic surfactant in a 1:1volume cosolvent mixture of isopropanol and heptane. The same procedurefor coating and drying was followed as in Example 1. Comparativeexamples A and B were again prepared as above. The following resultswere obtained.

Comparative C

[0060] A balloon coated with hydrogel coating 1 and followed with a topcoat of polymethylsiloxane. TABLE II Example 2 Comparative A ComparativeC Balloon Opening 27 58 24 Pressure (psi) Lubricity (grams) 6.5 6.0 15.0

[0061] Example 2 exhibited the overall best performance of low openingforce and low frictional forces.

Hydrogel Coating 2

[0062] A catheter useful for angioplasty having a small balloon with 2.5mm diameter and a length of 14 mm was used in this example. The balloonwas coated with a 3% solution of a high molecular weight poly(vinylpyrrolidone) with a dibutyltin dilaurate catalyst (both from AldrichChemical) in heptane by dipping. The coating was exposed to heat in a50° C. oven for 5 hours to facilitate crosslinking of the polymer.

Example 3

[0063] A solution of 6% chlorotrifluoroethylene (Aldrich Chemical) and20% polyoxyethylene modified silicone (Silwet® L-7002 from Witco) wasdissolved in a 1:1 ratio by volume of isopropanol:heptane. The hydrogelcoated balloon was treated with this second coating as in Examples 1 and2.

Comparative Example D

[0064] Hydrogel Coating 2 alone.

Comparative Example E

[0065] Hydrogel Coating 2 followed with a top coating ofchlorotrifluoroethylene. TABLE III Example 3 Comparative D Comparative EBalloon Opening 22 64 29 Pressure (psi) Lubricity (grams) 6.5 6.0 15.0

[0066] Example 3 exhibited the lowest opening force and comparablelubricity to the balloon coated only with hydrogel coating 2(comparative D).

1. A medical device for insertion into the body, said device having atleast one surface which periodically comes into contact with a secondsurface, said first surface comprising: a) a first lubricious hydrogellayer disposed on said first surface; and b) a second hydrophobic topcoating comprising at least one hydrophilic surfactant.
 2. The medicaldevice of claim 1 wherein said hydrogel layer comprises a polymericmaterial selected from the group consisting of polyalkylene glycols,alkoxy polyalkylene glycols, copolymers of methylvinyl ether and maleicacid, poly(vinylpyrrolidone), poly(N-alkylacrylamide), poly(acrylicacid), poly(vinyl alcohol), poly(ethyleneimine), polyamides, methylcellulose, carboxymethyl cellulose, polyvinyl sulfonic acid, heparin,dextran, modified dextran and chondroitin sulphate.
 3. The medicaldevice of claim 1 wherein said hydrogel layer comprises at least onehydrophilic polymer comprising polyethylene oxide.
 4. The medical deviceof claim 1 wherein said hydrogel layer comprises at least onehydrophilic polymer comprising poly(vinylpyrrolidone).
 5. The medicaldevice of claim 1 wherein said hydrophobic coating comprises ahydrophobic silicone compound.
 6. The medical device of claim 5 whereinsaid hydrophobic silicone compound is a siloxane.
 7. The medical deviceof claim 6 wherein said siloxane is dimethyl siloxane.
 8. The medicaldevice of claim 1 wherein said hydrophilic surfactant is selected fromthe group consisting of polyalkylene glycols, alkoxy polyalkyleneglycols, polyoxyethylene castor oil, and mixtures thereof.
 9. Themedical device of claim 8 wherein said copolymer of ethylene oxide is anethylene oxide/propylene oxide block copolymer.
 10. The medical deviceof claim 8 wherein said hydrophilic surfactant is a polyoxyethylenecastor oil.
 11. The medical device of claim 1 wherein said device is adilatation balloon.
 12. The medical device of claim 1 wherein saiddevice is a guide wire.
 13. The medical device of claim 11 wherein saidballoon comprises a polymeric material selected from the groupconsisting of polyether block amides, polyester block ethers,polyethylene terephthalate and nylon.
 14. A method for producing amedical device as in claim 1 comprising the steps of: a) coating saiddevice with a first coating of a lubricious hydrophilic polymericmaterial; and b) coating said device with a second coating of ahydrophobic material said hydrophobic material comprising at least onehydrophilic surfactant.
 15. A medical device for insertion into the bodycomprising a polymeric surface which is at least periodically subjectedto contact with at least one second surface said first polymeric surfacecomprising: a) a first lubricious hydrophilic coating disposed on saidfirst polymeric surface; and b) a second hydrophobic coating disposed onsaid first hydrophilic coating said hydrophobic coating comprising atleast one hydrophobic silicone compound and at least one hydrophilicsurfactant; wherein said first hydrophilic coating is biocompatible andsaid second hydrophobic coating inhibits said first hydrophilic coatingfrom prematurely up taking water and adhering to itself and saidhydrophilic surfactant acts as a carrier for said hydrophobic siliconecompound upon entrance into an aqueous environment.
 16. The medicaldevice of claim 15 wherein said device is a dilatation balloon.
 17. Themedical device of claim 15 wherein said hydrophilic coating is apolymeric material selected from the group consisting of polyalkyleneglycols, alkoxy polyalkylene glycols, copolymers of methylvinyl etherand maleic acid, poly(vinylpyrrolidone), poly(N-alkylacrylamide),poly(acrylic acid), poly(vinyl alcohol), poly(ethyleneimine),polyamides, methyl cellulose, carboxymethyl cellulose, polyvinylsulfonic acid, heparin, dextran, modified dextran and chondroitinsulphate.
 18. The medical device of claim 17 wherein said hydrophiliccoating comprises at least one polymer selected from the groupconsisting of copolymers of maleic anhydride and polycarboxylic acids.19. The medical device of claim 15 wherein said hydrophobic siliconecompound is a siloxane.
 20. The medical device of claim 15 wherein saidhydrophilic surfactant is selected form the group consisting ofpolyalkylene glycols, alkoxy polyalkylene glycols, ethoxylated castoroil, and mixtures thereof.
 21. A medical device adapted for insertioninto the body of a patient and manipulation from outside of the body,comprising an elongate body for insertion into said body wherein saidelongate body is coated with a first hydrogel polymeric layer and asecond hydrophobic coating wherein said hydrophobic comprises at leastone hydrophilic surfactant.